Insertion of medical devices through non-orthogonal and orthogonal trajectories within the cranium and methods of using

ABSTRACT

The invention comprises an elongated device adapted for insertion, including self-insertion, through the body, especially the skull. The device has at least one effector or sensor and is configured to permit implantation of multiple functional components through a single entry site into the skull by directing the components at different angles. The device may be used to provide electrical, magnetic, and other stimulation therapy to a patient&#39;s brain. The lengths of the effectors, sensors, and other components may completely traverse skull thickness (at a diagonal angle) to barely protrude through to the brain&#39;s cortex. The components may directly contact the brain&#39;s cortex, but from there their signals can be directed to targets deeper within the brain. Effector lengths are directly proportional to their battery size and ability to store charge. Therefore, longer angled electrode effectors not limited by skull thickness permit longer-lasting batteries which expand treatment options.

INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS

Any and all applications for which a foreign or domestic priority claimis identified in the Application Data Sheet as filed with the presentapplication are hereby incorporated by reference under 37 CFR 1.57. Thisapplication is a continuation application of U.S. application Ser. No.14/645,167, filed Mar. 11, 2015, which is a continuation application ofU.S. application Ser. No. 13/318,462, filed Nov. 1, 2011, which is aNational Phase Application of PCT International Application No.PCT/US2010/061531, filed Dec. 21, 2010, which claims priority benefit ofU.S. Provisional Application No. 61/288,619, filed Dec. 21, 2009, theentirety of each which is hereby incorporated by reference herein.

BACKGROUND Field

The present invention relates to medical devices, systems and methodsfor accessing cranial and intracranial structures. Specifically, theinvention is directed to altering brain function, and treating cranialand intracranial pathology. More specifically, the invention is directedto the surgical implantation of electrodes or other devices within orthrough the cranium to alter or improve brain function and pathologicalstates such as stroke, seizure, degeneration, and brain tumors. Mostspecifically, the invention is directed to minimizing surgical methodsand risks and maximizing the length of devices that can be implantedwithin or through the cranium and their ability to hold charge.

Description of the Related Art

Electrical stimulation of the brain can improve and ameliorate manyneurologic conditions. Examples of the success of brain stimulationinclude deep brain stimulation for Parkinson's Disease, tremor,dystonia, other movement disorders, epilepsy, and pain. Additionally,potential new sites of deep brain stimulation demonstrate promisingresults for other conditions such as obesity, depression, psychiatricdisorders, memory, migraine headache, and minimally conscious states.

Deep brain stimulation involves placing a long electrode through aburrhole in the cranium to a target deep to the surface of the brain.The electrode is placed under stereotactic guidance which is performedwith or without a frame. Frame based systems such as the Leksell framerequire that a rigid stereotactic frame is clamped to the skull througha number of screws that are fixed to the cranium. Frameless systemsutilize fiducial markers placed on the skin. In both methods, an MRI(magnetic resonance imaging) or CT (computed tomography) scan isperformed with the frame or fiducial markers in place. In frame basedstereotaxy, computer assisted reconstruction of the brain and targetarea is performed to localize the target in relation to the coordinatesof the frame. In frameless stereotaxy, a three-dimensionalreconstruction of the cranium and brain is matched to thethree-dimensional configuration of the fiducial markers. The end resultin both cases is the ability to place electrodes accurately intovirtually any part of the brain.

The cerebral cortex is another structure that yields a large potentialfor therapeutic intervention. In deep brain stimulation, the electrodepasses through the cerebral cortex as well as subcortical brainstructures to reach the affected deep brain nuclei and therefore risksinjury to the intervening healthy brain tissues as well as bloodvessels. These unnecessary yet unavoidable injuries can potentiallyresult in loss of brain functions, stroke, and intracranial hemorrhage.On the other hand, stimulation of the cerebral cortex is safer becauseelectrodes are placed on the surface of the brain or even outside thecovering of the brain, i.e. dura mater, a technique called epiduralelectrode stimulation. Additionally most of the subcortical or deepbrain structures have connections with known targets in the cortex,making these targets candidates for cortical stimulation. Accordingly,directly stimulating the cortex can affect subcortical and deep brainstructures that directly or indirectly communicate with the corticaltargets. Previous studies have demonstrated success in using corticalstimulation for the treatment of epilepsy, stroke rehabilitation, pain,depression, and blindness.

In addition to the treatment of pathologic conditions, brain stimulationand recording provides the virtually unlimited potential of augmentingor improving brain function. These technologies allow the brain tobypass dysfunctional neural elements such as due to spinal cord injury,amyotrophic lateral sclerosis (ALS), stroke, multiple sclerosis (MS),and blindness. Brain recording and stimulation techniques in these casesprovide a bridge for neural signals to cross injured or dysfunctionalelements both on the input as well as the output side. For example inthe case of ALS or a patient with locked-in syndrome, the patient isawake and conscious but without any ability to interact with theenvironment. These patients are essentially trapped within their brain.Recently, it has been demonstrated that by placing recording electrodesdirectly on the surface of the brain, these patients can learn tocontrol computer cursors and other devices through their own brainwaves.This method of direct control of external devices through brainwaves iscalled brain-machine interface

Brain-machine interface has also been implemented using brainwavesrecorded outside the cranium—electroencephalography (EEG), which detectsthe neural signals passing through the cranium with electrodes placed onthe scalp. Although noninvasive, brain-machine interface using EEGsignals is currently limited from the significant dampening of thebrainwave's amplitude by the cranium. Only the largest potentials amongthe brain signals are detectable by the EEG approach.

Similarly the cortex and some subcortical fibers can be activatedthrough the cranium by transcranial magnetic stimulation (TMS) ortranscranial direct current stimulation (tDCS). In this approach,magnetic waves (TMS) or electrical currents (tDCS) are activated on thescalp outside the cranium and transmitted through the cranium toactivate parts of the cortex and subcortical fibers. TMS has beeneffective in treating a number of disorders such as depression,migraines, and movement disorders. Additionally some reports suggestthat TMS may be able to boost memory and concentration. Similarly tDCSappears to improve some forms of learning when applied in low doses.This evidence suggests that stimulation of the cortex may have a large,virtually unlimited, variety of applications for treating centralnervous system pathology as well as enhancing normal brain functions.

Electrical stimulation has also been applied effectively for thetreatment of certain tumors. By applying an electrical field thatdisrupts the physiology of tumor cells, tumors have been found toshrink. Tumors in the brain, particularly those close to the surface ofthe brain such as meningiomas may also be treated by electricalstimulation. In addition to electrical fields, heat (thermoablation) andcold (cryoablation) have also demonstrated effectiveness towards tumors.

Prior art and current state of the art for brain stimulationtechnologies require the placement of electrodes either through acraniotomy where a flap of the skull is removed and then replaced, or aburr hole where a small hole is drilled in the skull and the brain canbe visualized. These procedures necessitate a minimum of an overnightstay in the hospital and pose risk to injury of the brain, due to theinvasiveness of the techniques. Additionally these “open” techniquespose special challenges for securing the electrode as most technologiesrequire a lead to exit the hole in the skull. Unless these electrodesare tethered by a suture or device, there is possibility of migration ormovement, particularly in the context of continuous pulsatile movementof the brain in relation to the skull.

Current techniques for cortical stimulation also risk the development ofscarring of the cortex as well as hemorrhage. With long term placementof foreign objects on the brain or spine, scarring (gliosis andinflammation) occurs. This is seen with both spinal cord stimulatorsplaced on the spinal cord as well as prostheses placed on the surface ofthe brain. Scarring distorts the normal brain architecture and may leadto complications such as seizures. Additionally, the placement ofdevices on the surface of the brain poses risks of hemorrhage. Aprevious clinical case illustrates the dangers: a patient who receivedsubdural cortical electrode implantation suffered significantintracranial hemorrhage after suffering head trauma. Thus in the case ofa deceleration injury like that seen in traffic accidents or falls, theimperfect anchoring of the electrode and the mass of the electode maycause the electrodes to detach and injure the brain. Blood vessels alsocan be sheared from the sudden relative movement of the electrode on thebrain, leading to subdural, subarachnoid, and cortical hematomas.However, if the electrodes were embedded within the skull then there isno risk of this type of shearing injury during traumatic brain injurysuch as from sudden impact accidents.

In order to expand the indications of brain stimulation to a largerpopulation of patients, the invasiveness of techniques for placement ofthe electrodes needs to be minimized. As many surgical specialties havedemonstrated, minimized surgical approaches often translate into safersurgeries with shorter hospital stays and greater patient satisfaction.

Recent advances in the miniaturization of microelectronics have allowedthe development of small, completely contained electrode systems, calledthe bion, that are small enough to be injected into muscle and otherbody parts through a syringe. This type of microelectrode devicecontains stimulation and recording electrodes, amplifier, communication,and power components all integrated into a hermetically sealed capsule.While some bion devices have batteries integrated with the unit, othersare powered by radiofrequency transmission. Although muscle and otherbody parts allow the implantation of bion electrodes, the cranium posesa challenge to the bion because the cranium is roughly 1 cm or less inthickness. This finite thickness limits the size of the electroniccomponents as well as the size of the battery. Battery capacity (theamount of energy stored within the battery) determines the length oftime between charges in a rechargeable battery and is effected by thelength of the battery. In the case of the bion, an injectable devicethat demands a small diameter, the battery capacity is directly relatedto the length of the battery. A longer bion electrode permits a longerbattery and hence greater battery capacity and a longer run time withoutrecharging.

Some patents exist covering implantable stimulators and electricalstimulation therapy systems. However, these patents are not speciallyadapted for insertion through the skull with multiple components througha single site by means of introducing some components at non-orthogonalangles.

In the present invention an electrode can communicate with and worktogether with other electrodes and supporting components (i.e.receivers, transmitters, batteries, rechargers, etc.) for an integratedtherapy system with multiple components insertable through the same

SUMMARY

The invention involves an improved method of implanting effectors,sensors, systems of effectors and sensors, and other implantable medicaldevices into the body through skin, bone, muscle, tissue, and otherintermediary material between an external surface of the body and theintended physical contact. The physical contact within the body may bethe target from which information is gathered with the sensors or towhich energy is directed with the effectors. Alternatively, the physicalcontact may be a transceiver station from which information is receivedby the sensor from another target (deeper inside) or from which energyis sent by the effectors to another target (deeper inside). Whenimplanted into the cranium the devices of the present inventiondescribed herein are referred to as a Cranion™.

The effector may include any component that produces or induces aneffect or acts as a stimulus at a target within the body. A preferredexample of an effector is an electrode producing an effect throughelectricity. Other types of effectors produce effects using magnetism,temperature, infrared radiation, light, vibrations, hypersonic energy(frequencies above human hearing), ultrasonic energy, radiowaves,microwaves, etc. and include transmitters of these other forms ofenergy.

The sensor may receive and record data relating to temperature, light,density, impedance, etc., in the form of radiowaves, microwaves,spectroscopy, etc.

According to a preferred embodiment, the invention focuses on improveddevices and methods for implantation through the cranium to providebrain therapy and therapeutic treatment of medical conditions having aneurological component.

The improved method involves modification of implantable devices tospecific sizes and shapes so that one or several can be insertedsimultaneously through a single entry site in the cranium by alteringthe insertion angle of each unit. The individual units are insertedorthogonally and/or nonorthogonally relative to the surface of thecranium tangent to the singular common entry site. The individual unitsmay be physically connected through a connector head at the common entrysite, thereby sharing electronics, power, and other attributes.Additionally, in some embodiments, the distal tip of the shaft and theshaft of the device may be configured so that the devices are insertabledirectly. By insertable directly it is meant that no or few other toolsor instruments are needed to make the entry site and/or the hole throughwhich the implanted device is inserted. For example, the device may beencapsulated in a helical externally threaded screw housing such thatthe shaft has a sharp distal tip allowing the whole device to piercethrough the skin and screw into bone similar to currently usedself-drilling cranial plating screws. The self-inserting characteristicenables electrodes to be inserted almost anywhere very quickly in aminimally invasive screw-in or pop-in procedure.

The types of medical devices that can be modified and implanted by themethods described in this invention are virtually unlimited and includeneural stimulation systems, neural recording systems, brain machineinterface systems, cryotherapy systems, thermotherapy systems, magneticfield generating systems, radiation emitting systems, auditory systems,iontophoresis systems, interpersonal communication systems,interorganism communication systems, et al. Currently, electrodes placedon or near the surface of the brain have been used clinically to treat anumber of disorders including seizures, pain syndromes, movementdisorders, psychiatric disorders, paralysis, and neurodegenerativedisorders like ALS. One preferred embodiment of the invention is toimplant one or more cortical stimulation and recording electrodes closeto the surface of the cortex through a single minimally invasive cranialentry site while enhancing the battery life and complexity of eachelectrode unit by allowing each unit to be greater in size (particularlylength) than the thickness of the skull since they are adapted forinsertion at an oblique angle and not limited to perpendicularinsertion. However, consistent with the present invention, someelectrodes (or other effectors) can be also be equal to or shorter thanthe thickness of the skull. Multicomponent devices and systems ofdevices with shorter electrodes (or other components) adapted forinsertion of shafts at a variety of angles permits more components thanpreviously possible through a single entry site. The electrodes may takethe form of an implantable microstimulator or improved bion that isembedded in the skull with its tip placed either epidurally (upon thedura mater) or subdurally (below the dura mater) near the surface of thebrain.

The thickness of the cranium is limited to a length of 5 mm to 10 mm. Ifelectrodes are inserted straight down, perpendicular (orthogonal) to thesurface of the cranium, their lengths would be limited to a maximum ofapproximately 1 cm. Electrodes longer than 1 cm that are implanted inthe cranium orthogonally would protrude through the skull into thebrain. Placement of electrodes into brain substance increases the riskof injury to brain and blood vessels both during the time of placementas well as afterwards given the physiologic pulsation of the brain inrelation to the cranium as well as during episodes of head trauma whichcauses acceleration and deceleration movement of the brain in relationto the cranium. Current methods of cortical stimulation place electrodeseither epidurally (outside the dura mater) or subdurally (in between thedura mater and arachnoid or epi-arachnoid). Placement of electrodes ineither of these locations provides for low impedance stimulation of thebrain while maximizing safety. Current methods of placement of corticalelectrodes necessitates drilling of a burr hole or craniotomy, both ofwhich pose risks to the patient and commonly require a stay in theintensive care unit to monitor postoperatively.

The current invention describes the method of insertion of devices andelectrode units through, orthogonal and nonorthogonal trajectoriesthrough the cranium. Angled insertion of the electrode units enableslonger units (length greater than skull thickness) to be used withoutpenetrating into the brain. The angled electrodes pass almost entirelythrough the skull and then just barely protrude towards cerebral cortex.Longer electrodes units are desirable because the length of a battery isproportional to the size and capacity of the battery. Thus longerelectrode units can contain longer and larger batteries. Preferably, thebatteries are rechargeable. However, regardless of whether the batteriesare rechargeable, it is desirable for the stimulation electrodes to havea maximum battery capacity (time until replacement or recharging).Higher capacity batteries provide sustained therapy and enhance patientmobility and freedom. The greater mobility and freedom provided byhigher capacity batteries in, longer electrodes increases theprobability of patient compliance for out-patient procedures because itis easier to comply with prescribed therapeutic regimens while living anormal life.

Longer electrodes units also allow more components to be integratedwithin each implant. Larger size allows flexibility in terms of thecomplexity of the circuitry, communication components, as well as theinclusion of both recording (receiving) and stimulation (transmitting)capabilities. Additionally, multiple electrode contacts can be placedwithin a single implant with greater ease, i.e. bipolar, tripolar,tetrapolar stimulation or recording within each electrode unit.

The ability to insert several electrodes units through a single cranialentry site is highly advantageous. The cranium obviously provides animportant protective function for the brain. Accordingly, it isdesirable to keep the cranium as intact as possible while accessing thebrain for therapy. Fewer entry sites in the cranium preserve itsintegrity and reduce the likelihood of the brain inadvertently beingexposed or harmed. However, if fewer entry sites imply fewer electrodesthis may have drawbacks with respect to the variety and intensity oftherapy that can be provided. The ability to insert several electrodesthrough a single site provides powerful therapy without jeopardizing thecranium and more importantly, the brain and blood vessels beneath. Whenmore intense therapy is not needed, multiple electrodes in the sameregion may still have advantages because they can be selectively,individually activated to prolong the time until recharging. Forexample, with electrodes radiating outward in a circle from a commoninsertion point, when the battery of the first electrode dies the systemcan automatically or manually advance to turn on the next electrode forit to begin stimulation. Additionally multiple electrodes positioned ina spatially dispersed pattern in two or three dimensional space allowsthe stimulating current to be steered in that space. Current steeringhas been utilized in spinal cord stimulation and is performed bydifferential activation of spatially distinct electrodes. Differentelectrodes or other components (i.e. sensors) inserted through a commonentry site may also be used to provide different therapeutic benefits(electrical stimulation, magnetic stimulation, drug delivery, etc.) orto gather different types of data (blood glucose level, temperature, pH,etc.).

The stimulation module is designed as either a single implant in asingle trajectory or multiple implants with multiple trajectories.Depending on the specific need of the individual, the stimulation modulemay contain one, a combination, or all of the following components:stimulation electrode(s), recording electrode(s), pulse generator,system control unit, battery, capacitor, current sink, data signaltransmitter, data signal receiver, receiver coil, transceiver,transducer, sensors, program storage, memory unit, internal electronics,analysis circuitry or software, etc. All of these components can becontained within a single implant similar to a Now However, thesecomponents can also be broken down into separate units that areimplanted in separate trajectories. Because the units pass through asingle entry site, they can be hard wired at this point Optionally, theymay communicate wirelessly with each other. For example, if anindividual wanted or needed an implant with a longer battery life, thenmultiple units composed of batteries can be implanted and wiredtogether. Since the battery units do not need to contain an electrode orpass through the inner table of the skull, battery units can beimplanted in a trajectory with the maximum length permitted by thecurvature of the cancellous portion of the cranium without passingthrough the inner or outer cortical layers of the cranium. Non-rigidunits that curve with the curvature of the cranium permit even longerimplants. These curved electrodes can slide into the cancellous skulltrapped in between the inner and outer cortical layers. The curvedstimulators and electrodes do not have to be stiff or rigid but can besemi-flexible to more easily slide into and maneuver within thecancellous space. In fact only the actual electrode contacts need topass through the cranium into the epidural or subdural space. All othercomponents can be implanted within the cranium without exiting thecranium. This system is customized with, the modules or componentsspecific for each individual, each brain target, and each specificpurpose or disorder that is being treated.

The implantable stimulating electrodes and associated componentsprovided herein have a plethora of uses. In addition to existingapplications of neuromodulation in Parkinson's Disease and epilepsy,they can be used to stimulate a healthy, normal brain to enhance memory,accelerate learning, etc.. (See Singer, Emily, “Want to Enhance YourBrain Power? Research hints that electrically stimulating the brain canspeed learning”, MIT Technology Review, Jun. 26, 2008; and Giles, Jim,“Electric current boosts brain power” in Nature, Oct. 26, 2004.) Theycan also be used on a damaged brain to stimulate regeneration, repair aswell as to record changes to enable a patient (including non-humanpatients such as animals) to communicate with the outside world simplyby using their brain. This offers hope for patients with paralysis afterstroke, spinal cord injury or other disorders (ALS, polio, etc). Anotherapplication is to use the implantable cranial electrode as means forbrainwave communication between people or other living organisms so thatwith training, one person (or other living organism, including otheranimals and potentially plants) can learn to recognize specific patternsof neural signals from another. In this manner it may be possible forpeople and other living organisms to have invisible, inaudibleconversations using only their thoughts and brain waves. This technologyhas important commercial as well as military applications. Additionallyimplantable units do not have to access the brain for communication;instead, vibrations generated by implants positioned elsewhere candirectly stimulate the inner ear for communication. For example, thestimulator (with multiple components at multiple angles through a singlesite) may be used as a transmitter and receiver in the inner ear withthe capacity to interact with a cell phone (such as via Bluetoothtechnology) for hands free conversation. Related ear devices have shownsuccess when used in partially deaf people (or other animals) totransmit auditory signals to the opposite ear as in cases of outer earor one-sided deafness.

Although electrode stimulation and recording has a wide potential ofuses mirroring those currently in use clinically, other preferredembodiments are plentiful. Another preferred embodiment is an implantthat uses temperature differences to activate or deactivate the brain orintracranial tissue. In this embodiment, the heat conducive element isimplanted through the cranium into the subdural or epidural space. Thecomponents that are implanted through other trajectories include thosedescribed in the electrode embodiment described above, but also includeheat pumps, thermogenerators, and thermoregulators. Cooling the braintypically deactivates the neural activity and can be utilized forseizures, migraines, pain, and other disorders.

The electronic circuitry of the present invention is amenable to variousconfigurations or embodiments. The invention covers the electroniccircuitry configurations of any conventional electrodes, stimulators,bions, etc. adapted for insertion of multiple components transverselythrough the cranium at orthogonal and/or non-orthogonal angles.

Other objectives and advantages of the invention will be set forth inthe description which follows. Implicit modifications of the presentinvention based on the explicit descriptions will be, at least in part,obvious from the description, or may be learned by practice of theinvention. Such subtle, predictable modifications and adaptations aretaken to be within the scope of the present invention. Additionaladvantages of the invention may be realized and obtained by means of theinstrumentalities and combinations particularly pointed out hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate embodiments of the invention, andtogether with the general description given above and the detaileddescription of the embodiments given below, serve to explain theprinciples of the invention.

FIG. 1 shows how the trajectory of each device or shaft at a particularentry site is defined by an axial angle (θ₁) (FIG. A) and a radial angle(θ₂) (FIG. B). The skull is represented by a hemi-sphere with 2 crosssections in (A) and 1 cross section in (B). FIG. 1A shows twonon-orthogonal trajectories both of which have the same axial angle (0₁) with respect to the perpendicular axis at the entry site. The radialangle (θ₂) is the angle on the tangent plane to the skin or skull at theentry site. For convention anatomic anterior orientation, i.e. thedirection towards the front of the face, or the component of theanterior orientation projected onto the tangent plane at the entry siteis taken as zero degrees.

FIG. 2 shows multiple devices from different entry sites, but angledsuch that they converge on the same target within a brain from differentdirections.

FIG. 3 shows multiple devices inserted from a single entry site atdifferent angles that are divergent from the entry site in order to aimat different targets within a brain.

FIG. 4 demonstrates the geometric relationship between the axial angleof device insertion (θ₁) and device length (l) for straight (non-curveddevices) that completely traverse a skull thickness (t) based on alateral displacement variable (x) when the device is fully inserted, sinθ=x/l.

FIG. 5 illustrates the relationship between the thickness or diameter ofthe device and the maximal length of the device when the device isimplanted at an increasingly greater axial angle (θ₁), i.e. greaternon-orthogonal insertional angle. FIG. 5A shows that a thinner devicewith smaller diameter can have greater length with greater axial angleof insertion (θ₁). However when the device has a diameter similar to thethickness of the skull, as shown in (B), the length of the device cannotchange with any axial angle of insertion (θ₁). FIG. 5B also shows thatas the axial angle increases, the tip of the larger diameter device isno longer able to penetrate the inner cortical layer of the skull.Instead the side of the device penetrates the inner cortex. In contrast,(A) demonstrates that a thinner device is still able to penetrate theinner cortex with the tip at greater axial angles (θ₁). Thus in general,non-orthogonal insertion of devices requires that the width or diameterof the device be less than the thickness of the skull.

FIG. 6 illustrates a device comprised of four multiple shafts andcomponents arranged in a linear array on the cortex. FIG. 6A. shows anbroad top view while (B) shows a side view, and (C) shows a view frominside the cranium. A single small burr hole is used to insert all fourshafts. The single burr hole is of partial thickness because the edgesat the bottom of the partial burr hole are used to guide the tips of theself-drilling shafts or drill bits. Two longer shafts flank two shortershafts resulting in a linear array as seen in (C) where four tips of theshafts are seen protruding through the inner cortex. A linear array ofstimulation as shown in FIG. 6 is useful for stimulation along a lineargyrus such as for motor cortex stimulation, where typically a smallcraniotomy is used to place a strip electrode.

FIG. 7 illustrates a device comprised of nine different shafts placedthrough a single partial small burr-hole. The overall configuration isdemonstrated in the cross section of the skull model with threedifferent views in (A), (B), and (C). A top view (D) and bottom view (E)demonstrate the arrangement of the contacts that penetrate through theinner cortex to affect the brain. Four shorter shafts are configured ina “+” configuration while four longer shafts are inserted in an “X”pattern. A central shortest shaft is inserted last. This configurationresults in a 3 by 3 matrix of components that can reach the cortex. Thistype of configuration is useful for epilepsy stimulation where thecentral electrode senses seizure activity at the seizure focus. Thiscentral electrode then activates its own stimulation electrode to abortthe seizure. At the same time, the 8 surrounding ring of electrodes areactivated as well. The activation of the ring of electrodes help to trapand cancel the spreading wave of seizure activity from the centralepileptogenic focus. Such a configuration would generally necessitate acraniotomy; however this configuration is placed through a singlepartial burr hole.

FIG. 8 illustrates a shaft inserted at an axial angle that serves as aconduit for a guidable and steerable epidural or subdural electrodearray. FIG. 8A. shows the drilling of a non-orthogonal hole through thecranium by a self-drilling shaft. In (B), an inner compartment of theshaft is unlocked and removed from the outer threaded portion, leaving acylindrical conduit. This conduit allows one or more electrode arrays tobe inserted into the epidural or subdural space (C). The angled,non-orthogonal trajectory of the shaft allows the electrode array tosafely slide into the epidural or subdural space at a shallow angle. Incontrast if the burr hole were orthogonally oriented, the electrodearray would have to make a 90 degree turn after passing through theskull. The electrode arrary can be directed similarly to spinal cordstimulation electrode array using mechanical turning by a small bend inthe distal tip of the inner stylet. Alternatively, the distal innercannular may be ferromagnetic allowing an external magnetic orelectromagnetic field to guide or direct the tip of the electrode array.Lastly, a fibroptic inner cannula with distal camera would allowendoscopic guidance of the electrode array under direct visualization ofepidural, subdural, or intraventricular structures. The tip of thestylet also would allow for stereotactic image guidance by emittingsignals such as radiofrequency or sonic/ultrasonic impulses that helplocalize the distal tip in stereotactic coordinates. Once the target anddesired placement of the electrode array has been accomplished, theproximal end is secured to the cranial conduit/shaft by a lockingmechanism. Alternatively, other components such as a battery,controller, transducer, etc. can also be placed inside the cannula, orin other trajectories through the cranium from the same entry site. Thecombination of multiple shaft placement through a single entry site withmultiple steerable electrode arrays allow a limitless configuration ofbrain stimulation and recording through a single small burr hole.

FIG. 9 demonstrates a simple connection system to physically linkmultiple shafts and components that are placed through a single ornearby entry sites. The connector shown is a multichannel connector, butany connector would suffice including USB or micro USB connectors. Whilethe components can communicate wirelessly with each other with theappropriate components included within the shaft, some functions aremore efficient through direct physical connections.

FIG. 10 demonstrates a preconfigured head unit used to facilitate theplacement of multiple shafts and multi-component arrays. FIG. 10A. showsthe empty head unit with three docking stations. FIG. 10B shows theinsertion of a single shaft into one docking station. Two shafts areinserted into the head unit in (C), while all three shafts have beeninserted in (D). The head unit allows direct communication andconnection between all shafts and components of the shafts. The headunit itself can also contain multiple components of the overall devicesuch as battery, communication systems, transducers, etc. The head unitcan be inserted into a pre made burr hole or be self-inserted by havinga self-drilling and self-tapping pointed tip. The head unit does notneed to have its own fixation to the skull as the insertion of shaftsthrough the docking stations acts to lock the docking station into theskull. Each docking station can also have adjustable angles of insertionby having a rotating ball and socket mechanism as the docking stationthrough which shafts are inserted.

FIG. 11 shows a flow chart of a method of implanting the devicesdescribed herein: (I) identify the target, (II) create an incision,(III) drill a partial thickness burrhole, (IV) identify target and depthfrom partial thickness burrhole, (V) insert device(s), and (VI) closewound.

DETAILED DESCRIPTION

The present invention and method of its use enables multiple effectors,sensors, and other components to fit through a single entry site toprovide improved and/or longer-lasting therapeutic benefits. Accordingto some embodiments this is accomplished by inserting the effectors,sensors, other components, or shafts housing any of these elements atdifferent angles to permit greater subsurface reach given a smallsurface entry site. As used herein, the term “entry site” includes oneor more physically distinct openings, holes, or incisions, within closeproximity to one another and taking up a relatively small total area ofspace consistent with minimally invasive surgical procedures. Thus, an“entry site” may be one opening or hole but is not limited to such. The“entry site” may also be an entry zone, area, or region that encompassestwo, three, four, or more distinct openings.

For each entry site, the stimulator/sensor devices may be inserted atseveral different axial angles between an axis perpendicular to theskin's surface (straight down) and a plane tangent to the skin's surfaceat the entry site. The effectors (i.e. electrodes) and/or sensors mayalso be inserted at several different radial angles around the peripheryof an entry site in the plane of the tangent to the entry site. Thelocation of the entry site, the axial (θ₁) and the radial (θ₂) insertionangles determine an unique trajectory in the skull and in the body.Preferably, no two stimulator/sensor devices (comprising at least oneeffector or sensor as part of the device) have the same set of axial(θ₁), radial (θ₂) angles, and entry site location so that each device(and each effector or sensor therein) occupies a unique positiondifferent from the others. The closer the first diagonal axial angle isto parallel to the skin surface, the longer the effector or sensor canbe while still traversing substantially laterally through the skullwithout reaching the brain. Conversely, the closer the first diagonalaxial angle is to perpendicular to the skin's surface (straight down),the shorter the effector or sensor must be because it is moving moreclosely to vertical though the skull and is thereby more strictlylimited by the skull's vertical thickness. (See FIG. 1.)

Angled implantation allows implantation of extra components to supportor work together with the effector or sensor (i.e. electrode) to form alonger-lasting system or improved bion. For example, the main device maybe implanted perpendicularly but one or more components (i.e. extendedbatteries or battery packs) are implanted at an angle. This allows extracomponents that support a main electrode to be embedded within the skullat an angle. More supporting batteries prolongs the life of theelectrode while effectively breaking up the overall implant into severalcomponents that are connected (i.e. at the top) by a connector head orconnector. Other components, in addition to batteries, can betransmitters, receivers, radio transceivers, heat generators, coolingdevices, magnetic coils, capacitors, transformers, ultrasonictransducers, hypersonic emitters/receivers, electrophysiologicalrecording means, sensors, iontophoresis means, optical stimulators,lasers, cameras, address/positioning units, etc.

As used herein, the term “component” includes effectors and sensors butis not limited to these categories. “Component” might also include othercategories of auxiliary, complimentary, or supplementary elements thatsupport an effector or sensor but do not themselves produce an effect ona body or sense (gather data) directly. For example, “component” mightinclude a buffer solution, a physical cushion, a catalyst, a battery, avacuum line, etc. The present invention includes an implant in which atleast one component is an effector or sensor. The implant may alsoinclude other additional, components that are also effectors or sensors,or are neither effectors nor sensors.

The implantable devices described herein are made of biocompatiblematerials. In a self-inserting embodiment the devices need to be made ofmaterial sufficiently durable and hard to penetrate bone withoutrupturing. In embodiments that rely on pre-drilling a hole more materialoptions are possible and softer, more flexible materials may be used toencapsulate or house the device. According to a preferred embodiment, atleast a portion of the device is made of a semi-permeable material thatabsorbs some molecules, transmits (flow through) some molecules, elutessome molecules, and blocks some molecules. Such a semi-permeablematerial may be a mesh with openings (for example, tiny nanopores)therein that optionally also includes key cells or molecules (thatprovide an auxiliary function) embedded therein on its surface.

According to a preferred embodiment, the effectors are electrodes andsupporting components (i.e. transmitters, receivers, etc.) of thepresent invention are designed to be insertable directly or to insertthemselves. By “insert themselves” or “insertable directly” it is meantthat the components do not require burr holes to be created in the skullwith a drill prior to implant and/or that the components do not requireexpulsion through an introducer (i.e. needle, cannula, etc.). Selfinserted screws of this type are typically classified as self-drillingand self-tapping, in that they do not need a pilot hole nor does thehole need to be tapped to form the threaded tract for a screw. Thismight be accomplished by the components having distal tips that aresharp or a housing that resembles a screw shaft with threads.

Alternatively, the cranial stimulator devices can be helical in shapesuch that they wind into the bone in a manner similar to coil anchorsfor sand volleyball nets. The distal tip of the helix enters into asmall hole and the curved tail of the device follows.

When drilling into the skull is necessary such as due to increasedresistance from bone making self-tapping screws inadequate, a preferredsystem and method involves using a balloon along one or more sides ofthe stimulator device. Drilling often creates a hole that is slightlylarger than necessary or imperfect in shape such that there is not atight fit for the screw. The balloon can be filled with air and or fluidafter insertion in a deflated condition to close the gap, reducing theimperfect mating between drill hole and stimulator to provide animproved friction fit that renders the stimulator less susceptible tointernal drift/migration. The balloon can also be used proximally abovethe stimulator to push the electrode contacts on its opposite distal endinto closer contact with the surface of the cortex.

If the effectors contain, are coated with, or are associated withmagnetic means (i.e. coils, magnetic materials, etc.) they can be usedto provide magnetic stimulation therapy in addition to electricalstimulation therapy. Magnetic energy can also be used to recharge theelectrical batteries. For example, inserting a magnetic coil inside theskull enables one to carry out local magnetic stimulation (“intracranialmagnetic stimulation”) with a much lower intensity than that used fortranscranial magnetic stimulation which requires a large enough magneticfield to travel through the cranium (resulting in a diminution of signalstrength in the process) and, also is not localized. The inability tolocalize therapy, also known as poor selectivity, typically results inoverbroad application that may cause damage to unintended surroundingregions and too weak an intensity of treatment at the target site. Theability to localize therapy overcomes both of these drawbacks tosystemic application.

In addition to electrical and magnetic stimulation the implantableelectrode or components associated with it can be used to generate heator cold. Heat and cold have been shown to influence brain activity suchthat they can be used to complement, supplement, or as an alternative toelectrical and/or magnetic stimulation.

In addition to electrical and magnetic stimulation the implantableelectrode or components associated with it can be used to generate heator cold. Heat and cold have been shown to influence brain activity suchthat they can be used to complement, supplement, or as an alternative toelectrical and/or magnetic stimulation.

In different embodiments the effector batteries can be recharged insideor outside the body or inside the body through connection to a chargingdevice outside the body. According to a preferred embodiment theeffector batteries are recharged inside the body through a naturallyoccurring means including changes in heat, fluid dynamics, etc.. Thebatteries may include a thermogenerator or thermoelectric generator thatuses local heat in situ to generate power. Or, the batteries may includea mechanical power generator that uses natural pulsation of the brainrelative to the cranium and changes in cerebrospinal fluid pressure toharness and store energy.

In addition to built-in electrode batteries, the implantablesensor-effector devices of the present invention may be powered by anynumber of alternative means. In order to reduce their size, they may bepowered from outside through a means for receiving energy with the meansfor receiving energy being smaller than a conventional electrodebattery. More specifically, they may rely upon ultrasonic, hypersonic,or radiofrequency energy from a source at another location in the bodyor outside the body that is absorbed and channeled through a receivingplatform. These alternative sources of energy permit the devices to besmaller because a built-in battery is not required. Thus, the device maybe made on the scale of microns (length, width, height) rather than,millimeters and inserted more deeply into the body, into smallerchannels and crevices, or through intact bone and muscle for betteraccuracy while still being minimally invasive and without sacrificinganatomical structural integrity. Another advantage of the energy sourceand some of the electronic complexity being outside the body is that itis easier to upgrade and modify from outside. Another advantage ofeffectors radiating downward and outward from an entry site at differentangles is that when a target region for stimulation is deeper within thebrain the angle(s) can be set so that rays from more than one effectorconverge precisely on the deeper target. More than one entry site can bemade so that several different devices from several different entrysites converge on the target from different directions (see FIG. 2).Alternatively, when there is more than one target region deep within thebrain, effectors from a single entry site can be used to simultaneouslyreach several different regions by directing the effectors at differentangles (see FIG. 3). If the effectors were limited to non-angled,conventional, straight-down insertion all effectors (even throughmultiple entry sites) would be pointed at the core or center of thebrain without the ability to provide targeted therapy to intermediateregions of the brain between the core and the cortex.

In alternative embodiments, the effectors may have additionalcharacteristics that enable them to jointly maximize length and distancewithin the skull. For example, the effectors may curve with a radius ofcurvature that approximately matches the radius of curvature or shape ofthe skull. Since the cranium is composed of three layers, a hard innercortical layer, a hard outer cortical layer, and a softer cancellousmiddle layer, long components can be pushed through the cancellous layerbeing trapped by the harder inner and outer cortical layers.Additionally, the devices may branch out (for example, telescopically)once inserted to form an intracranial pathway that provides additionalbattery power storage space. However, because the branches would have totraverse through the somewhat hard bone of the cranium these(bifurcated, trifurcated, poly-furcated) embodiments would probablyrequire separate insertion tools capable of drilling worm-like tunnelsfor the branched devices.

When the effectors are electrodes the circuitry of the present inventionfor all embodiments is variable. By electronic circuitry it is meant thearrangement and interrelationship between electrodes, batteries,connectors, coils, transmitters, receivers, transceivers, capacitors,controllers/programming means, address means, pulse control means,sensors, etc. Any configuration of these elements that is functional formultiple electrodes inserted transversely through a single entry site(at orthogonal and/or non-orthogonal angles) is consistent with thescope of the present invention.

In other embodiments, the configuration of electronic circuitry isdistinctly different in one or more features from conventional productsand patent claims, which serves to further distinguish the invention inaddition to its other distinguishing features.

As discussed previously, as neurostimulators the devices of the presentinvention have a myriad of established applications to improvepathologies (movement disorder, psychiatric conditions) and enhancenormal functions (learning, memory) in the neural system, particularlythrough direct interaction with the brain. Additional, potentialapplications include peripheral nerve stimulation and interaction withother biological systems to catalyze and regulate healing processes. Forexample, implantable stimulators as described herein may be used atsites of bone fracture or disc degeneration to expedite new boneproliferation as a substitute or supplement to biological or chemicalmeans (bone cement, bone graft, bone filler, bone glue, hydroxyapatite,ground bone composition, or another bone substitute). One specificapplication is use of stimulators around pedicle screws used in pediclescrew stabilization/fusion of adjacent vertebrae to stimulate boneregrowth over the screws to better camouflage the implants.

According to a preferred embodiment, the devices described herein areused to enable communication between two or more entities with at leastone entity being a living organism. The other entities may be otherliving organisms of the same or a different species as the first livingorganism, or may be a machine including but not limited to a computer, alaptop, a cell phone, a personal digital assistant (PDA), a keyboard, acamera, a wheel chair, a bicycle, a car, etc. The communication can beone-way, two-way, or a multi-channel exchange amongst several differententities (group conversation or different entities all communicatingwith a centralized hub).

In this method of enabling communication between at least one livingorganism and at least one other entity a device comprising an effectorand a sensor is implanted in the living organism. At least oneadditional component is implanted in the other entities to interact withthis device. The sensor in the first entity (living organism) gathersdata and generates a pulse that transmits the data to the otherentities. The other entities receive the pulse through their componentsthat read and translate it. In this manner the first entity (livingorganism) can relay information or “talk” to the other entities in openloop communication. In an alternative embodiment, the device in thefirst entity further comprises at least one feedback component and thecommunication is closed loop with the feedback component in the firstentity verifying receipt of the pulse from the first entity by thesecond entity.

When receivers or transceivers are used to receive signals they may beused alone to receive signals directly or they may be used inconjunction with one or more intermediary devices that relay and/orprocess the signal prior to its reception. The intermediary device mightamplify or reformat the signal and eliminate noise. In some embodiments,for some applications, the intermediary device could be somethingsimilar to a bluetooth earpiece, a cell phone, a wife router, an aircard, etc. Likewise, when effectors are used to induce an effect in anentity (machine or organism) they may induce the effect directly orthrough one or more intermediary devices that adjust or process the rawinformation and energy they provide.

The devices described herein are contemplated to be adaptable for usewith state-of-the-art sixth sense and mind control devices. Theminimally invasive implants of the present invention may be moreconvenient than headgear and may be used to read neural states andobjectives to initiate actions in the outside world rather than relyingon hand gestures from the living organism subject or patient. As usedherein (before and after), the term “patient” refers to any object thatsubjects itself or is subjected to a treatment incorporating the presentinvention. A “patient” need not be an ill person or someone withphysical, emotional, or psychological impairments or abnormalities. Infact, a “patient” need not be a human being or even a living organism. A“patient” may include completely healthy, happy, and successfulorganisms or objects that choose to subject themselves to treatment orare subjected to treatment with the present invention in order tofurther their abilities and become even more successful or to improvecertain functions.

Examples of conditions the devices of the present invention can be usedto treat include: psychological conditions generally, genetically orbiologically based psychological conditions, depression, acute mania,bipolar disorders, hallucinations, obsessions, obsessive compulisivedisorder, schizophrenia, catatonia, post-traumatic stress disorder, drugand alcohol addiction, Parkinson's disease, Alzheimer's disease,epilepsy, dystonia, tics, stuttering, tinnitus, spasticity, recovery ofcognitive and motor function following stroke, pain syndromes, migraine,neuropathies, back pain, internal visceral diseases, urinaryincontinence, etc.

Specific medical applications include using the cranial implants of thepresent invention as follows: (i) enabling a paralyzed man to sendsignals to operate a computer by “telepathically” moving a mouse,cursor, or typing on a keyboard, improving one's ability to work; and(ii) enabling a paralyzed man to send a signal causing a machine orcomputer to speak a phrase or message for them so that they can,communicate their needs, desires, and thoughts to others and the world.

Specific entertainment and social applications include using the cranialimplants of the present invention as follows: (i) a person has aCranion™ implanted so that he can use it to control his iPhone or Wiigame console without using his hands or in addition to hand controls;and (ii) a person has a Cranion™ implanted to communicate with one ormore other persons, each with his own Cranion™ implanted to enableprivate “telepathic” conversations in a group of people including at ameeting, in church, in the courtroom, at a sporting event, and during acard game.

Implanted devices of the present invention (especially those in thebrain) may be used to control a projector, a camera, a laser, a bar codereader, etc. worn on the body. Such sixth sense and mind control devicesmay find application for video games, electronic transfers of money,trading stocks, shopping, social and professional networking and storageof data about people, filming, photography, etc. The implants could beused to read expressive conditions (facial expressions, gestures) andemotional experiences (affective response) of the living organism inwhich they are implanted or of others with whom the patient comes incontact. The implants could then, process and analyze this informationto initiate cognitive actions in response thereto.

It is known that an electrical signal at the cortex of the brain looksrandom across the population for the same thought, even though itoriginates from the same region of the brain, due to a unique foldpattern of each person's brain similar to fingerprints. Headgear uses amathematical algorithm to unlock the random signal to make it consistentacross the population. Alternatively, the implants of the presentinvention might be used (i) to read the signal from a source in thebrain beyond the cortex where it is uniform without the algorithm, (ii)apply the algorithm to data read at the cortex, or (iii) to provide aninitial equilibration process that compensates for the differences insignals from one person to another.

According to still other embodiments, the Cranion™ has a longerelectrode lead that passes through the skull at an angle and goesepidural to distant areas like a spinal cord stimulator sliding up theepidural space in the spine. This tip may then be steerable, forexample, with a magnet.

The general method, as summarily illustrated in the flow chart of FIG.12, in greater detail may encompass the following sequence:

1.) Use stereotactic localization, either with a frame or framelessstereotactic localization to identify a target(s);

2.) Decide on a configuration. For example, either single electrode,multiple around the single target, single line (see FIGS. 7 and 8);

3.) Single stab incision 5-10 mm;

4.) Drill 2-4 mm partial thickness burrhole (this allows an “edge” sothat drills can be angled into the corner and an off angle trajectorycan be accomplished;

5.) Use stereotactic localization to identify target and depth away fromthe central partial burrhole;

6.) Plan trajectory based on the target and either drill a pilot hole oruse a self drilling, self tapping Cranion™ to insert the Cranion™device;

-   -   6a.) Drilling a pilot hole allows exact knowledge of the depth        of the hole however a cannulated Cranion™ in which the sharp tip        can be removed (see FIG. 9) also allows a portal to determine        whether the epidural space has been entered

7.) Place other Cranions™ and connect them with wires (see FIG. 9) orhave them connect wirelessly. Or, use the head device.

8.) Add other components such as extra batteries that don't need to goall the way out of the skull.

9.) Close the wound

The present invention is not limited to the embodiments described above.Various changes and modifications can, of course, be made, withoutdeparting from the scope and spirit of the present invention. Additionaladvantages and modifications will readily occur to those skilled in theart. Therefore, the invention in its broader aspects is not limited tothe specific details and representative embodiments shown and describedherein. Accordingly, various modifications may be made without departingfrom the spirit or scope of the general inventive concept as defined bythe appended claims and their equivalents. As used in the claims theconjunction “or” means the inclusive or (and/or, either elementindependently or any combination of the elements together).

1. (canceled)
 2. A device that creates an effect on a target site orthat gathers data about a target site in a patient's body, comprising: afirst shaft configured to be inserted through skin, muscle, tissue,bone, or skull; and at least one component, including an effector and/orsensor, housed within, passing through, or attached to the first shaft;wherein the shaft is configured to be self-inserting through an entrysite in an absence of a premade hole, said first shaft having a diameterof less than 1 cm.
 3. The device of claim 2, wherein the first shaft isconfigured to be self-inserting, at the entry site, orthogonally to atangent of a surface at the entry site.
 4. The device of claim 2,wherein the first shaft is configured to be self-inserting, at the entrysite, at an angle between parallel and perpendicular to a tangent of asurface at the entry site.
 5. A system of devices according to claim 2,wherein two or more devices are configured to be inserted through theentry site, such that the entry site is common to two or more devices.6. The system of claim 5, wherein at least one device is configured tobe inserted orthogonally to a tangent of a surface at the entry site. 7.The system of claim 5, wherein each device comprises a single shaft andall components of that device are housed within that shaft.
 8. A methodof creating an effect on a target site using the device of claim 2,wherein the device has at least one effector, comprising: inserting thedevice of claim 2 at an oblique angle at the entry site; and activatingthe effector.
 9. A method of gathering data about a target site usingthe device of claim 2, wherein the device has at least one sensor,comprising: inserting the device of claim 2 at an oblique angle at theentry site; and receiving data through the sensor.